Preheat the oven to 325˚F. Line an 8x8-inch baking pan with foil, with a 1-2-inch overhang (you’ll use this to pull out the brownies later). Spray the foil with cooking spray, or brush with it with oil.
For the pumpkin cheesecake batter, in a mini food processor, combine all of the ingredients and blend, stopping and scraping once or twice, until smooth. Set aside.
For the brownie batter, place the chocolate and butter in a large heatproof bowl set over a pot of simmering water (the water shouldn’t be touching the bottom of the bowl). Stir often until the butter and chocolate are melted and smooth.
Remove the bowl from the heat, and whisk in the sugar, vanilla and salt. Let cool until lukewarm. Whisk in the eggs. Add the almond flour and brown rice flour, and mix until completely incorporated. Scrape the batter into the prepared pan and spread it in an even layer. Pour the pumpkin mixture over top, and tilt the pan to spread it evenly. Using a spatula, gently nudge the pumpkin batter into the corners so that it’s in an even layer.
Bake 30 minutes, turning the pan halfway through, or until set—the top should look matte and there should be small cracks around the edges (a toothpick inserted in the center will not come out clean). Let cool in the pan on a rack (about 30 minutes), then refrigerate, uncovered, until chilled, about 1 hour. Once the pan is chilled, cover it with plastic wrap then pop it back in the fridge until you’re ready to serve (the brownies can be refrigerated for up to 3 days).
Gripping the foil, remove the brownies from the pan. Cut the brownies into squares and serve!